Sometimes, despite all best efforts, a cut can fail. USB connection, chain slippage, whatever. This may seem like the most basic of tips to save things, but after reading a few threads recently, I thought worth sharing.
When you set define home for your cut, use the Z-axis control and drill a hole; if you need to resume a cut, this is your known zero. I’ve found that if I reset my chains knowing the mm X Y start it’s sometimes off; but manually jogging till your bit can CLEANLY enter and exit that known zero always helps.
I hope this helps just one person - saved me a few times now
I start often using my phone in webcontrol that way I can screenshot the home position before starting. If there are issues, manually put in the home position and then restart at the last line number. This is tricky if you have M3/M5 spindle control and may require a line added to the gcode, but is quickly done.
I usually go to the last cut Z move, edit off the intervening code up to the initial header, rezero to the 0,0 mark (nice to dimple it), and G0 to the last XY (and maybe a little upwards Z) move before the Z movement. On Windows, so shift-pgup (iirc, muscle memory) helps trim off all those unneeded gcode lines. Hadn’t thought of screenshots but will try that next time.